Process for producing α,α,α,α',α',α'-hexachloroxylene

Abstract

This invention concerns to a process for α,α,α,α',α',α'-hexachloroxylene by reacting m-xylene or p-xylene or a partially chlorinated product thereof with chlorine under the irradiation of ultraviolet rays, the process comprising (1) a first-step chlorination reaction which is carried out in the presence of α,α,α,α',α',α'-hexachloroxylene as a solvent added at the initial stage of the reaction, and continued until a compound convertible to α,α,α,α',α',α'-hexachloroxylene by chlorination becomes substantially absent in the reaction mixture, and (2) a second-step chlorination reaction which is continued from the first-step chlorination and carried out to convert difficulty-separable by-products present in the reaction mixture to easily-separable compounds. This invention also concerns to a process for producing an aromatic dicarboxylic acid chloride which comprise reacting the resulting α,α,α,α',α',α'-hexachloroxylene with isophthalic acid or terephthalic acid.

What we claim is: 
     
       1. A process for batchwise or continuous production of α,α,α,α',α',α'-hexachloroxylene by reacting a xylene compound selected from the group consisting of (i) xylene selected from m-xylene and p-xylene and (ii) compounds resulting from the partial chlorination of the side-chain methyl groups of the xylene (i), with chlorine under the irradiation of ultraviolet rays; said process comprising 1. a first-step chlorination reaction which is carried out in the presence of α,α,α,α',α',α'-hexachloroxylene as a solvent added at the initial stage of the reaction, and continued until a compound convertible to α,α,α,α',α',α'-hexachloroxylene by chlorination becomes substantially absent in the reaction mixture, and   2. a second-step chlorination reaction which is continued from the first-step chlorination and carried out to convert difficulty-separable by-products present in the reaction mixture to easily-separable compounds.   
     
     
       2. The process of claim 1 wherein the amount of the α,α,α,α',α',α'-hexachloroxylene added as a solvent at the initial stage of the reaction is 0.3 to 15 times the weight of the starting xylene compound when the process is carried batchwise, and 40 to 99% by weight of the reaction mixture when the process is carried out continuously. 
     
     
       3. The process of claim 1 wherein the concentration of chlorine in the second-step chlorination reaction is lower than that in the first-step chlorination reaction. 
     
     
       4. The process of claim 1 wherein the xylene compound is m-xylene or p-xylene. 
     
     
       5. The process of claim 1 wherein after the end of the second-step chlorination, the reaction mixture is distilled to separate and remove impurities.